Why does my soft-body fly around?
Okay the problem of flying around appears to be the collision ball size calculation. You had it set to average. When I set it to minimal, it worked. I admit, I have no idea why this happened, it may have been a collision fight with the plane, but changing it does fix your problem. 

I also tweaked a few other settings to get it to look like the target animation, it's not perfect, but it's better than what you had. :)


Turned off Stiff quads (you don't want anything stiff on this guy.)
Turned friction up to 1.00 (that may have been part of your problem, he's as slippery as an eel) 
Angled him a little so his legs don't fold up. (didn't work real well, but I'm sure if you try you can get it right)
And (optional) changed skin texture to something shiny so I could see bounding and stretching problems. (also that skin texture is disturbing :D)


So the effect isn't quite right, but hey! he doesn't head for Florida every time you hit play. Noodling him is your job as the artist. Have fun...